secp256k1_sys

Function secp256k1_xonly_pubkey_serialize

Source 
pub unsafe extern "C" fn secp256k1_xonly_pubkey_serialize(
    cx: *const Context,
    output32: *mut c_uchar,
    pubkey: *const XOnlyPublicKey,
) -> c_int
Available on non-secp256k1_fuzz only.